Question 65193

Let x=cost of 1 doughnut
And y=cost of 1 coffee

Now we are told that mike paid $2.98 for 3 doughnuts and 2 coffees

so 3x+2y=$2.98

Next day we are told that Mike paid $1.64 for 2 doughnuts and 1 coffee
That would be 2x+y=$1.64

Now we have our two equations:

(1)  3x+2y=$2.98
(2)  2x+y=$1.64 

Multiply Equation #(2) by (-2) and we get:

(2a) -4x-2y=-$3.28
(1)   3x+2y=$2.98

Add (1) and (2a) and we get:
-x=-$.30
x=30 cents cost of 1 doughnut

substitute in (1) and we have:

3($.30)+2y=$2.98
$.90+2y=$2.98  subtract $.90 from both sides:
2y=$2.98-$.90
2y=$2.08
y=$1.04  cost of 1 coffee

ck substitute in (1)

3($.30)+2($1.04)=$2.98
$.90+$2.08=$2.98
$2.98=$2.98

Substitute in (2)
2($.30)+$1.04=$1.64
$.60+$1.04=$1.64
$1.64=$1.64


Hope this helps.  Happy holidays.----ptaylor